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AimsPhylogenetic diversity metrics can discern the relative contributions of ecological and evolutionary processes associated with the assembly of plant communities. However, the magnitude of the potential variation associated with phylogenetic methodologies, and its effect on estimates of phylogenetic diversity, remains poorly understood. Here, we assess how sources of variation associated with estimates of phylogenetic diversity can potentially affect our understanding of plant community structure for a series of temperate forest plots in China.MethodsIn total, 20 forest plots, comprising of 274 woody species and 581 herbaceous species, were surveyed and sampled along an elevational gradient of 2800 m on Taibai Mountain, China. We used multi-model inference to search for the most parsimonious relationship between estimates of phylogenetic diversity and each of four predictors (i.e. type of phylogenetic reconstruction method, phylogenetic diversity metric, woody or herbaceous growth form and elevation), and their pairwise interactions.Important FindingsThere was no significant difference in patterns of phylogenetic diversity when using synthesis-based vs. molecular-based phylogenetic methods. Results showed that elevation, the type of phylogenetic diversity metric, growth form and their interactions, accounted for >44% of the variance in our estimates of phylogenetic diversity. In general, phylogenetic diversity decreased with increasing elevation; however, the trend was weaker for herbaceous plants than for woody plants. Moreover, the three phylogenetic diversity metrics showed consistent patterns (i.e. clustered) across the elevational gradient for woody plants. For herbaceous plants, the mean pairwise distance showed a random distribution over the gradient. These results suggest that a better understanding of temperate forest community structure can be obtained when estimates of phylogenetic diversity include methodological and environmental sources of variation.

Background Escherichia coli are mostly commensals but also contain pathogenic lineages. It is largely unclear whether the commensal E. coli as the potential origins of pathogenic lineages may consist of monophyletic or polyphyletic populations, elucidation of which is expected to lead to novel insights into the associations of E. coli diversity with human health and diseases. Methods Using genomic sequencing and pulsed field gel electrophoresis (PFGE) techniques, we analyzed E. coli from the intestinal microbiota of three groups of healthy individuals, including preschool children, university students, and seniors of a longevity village, as well as colorectal cancer (CRC) patients, to probe the commensal E. coli populations for their diversity. Results We delineated the 2280 fresh E. coli isolates from 185 subjects into distinct genome types (genotypes) by PFGE. The genomic diversity of the sampled E. coli populations was so high that a given subject may have multiple genotypes of E. coli, with the general diversity within a host going up from preschool children through university students to seniors. Compared to the healthy subjects, the CRC patients had the lowest diversity level among their E. coli isolates. Notably, E. coli isolates from CRC patients could suppress the growth of E. coli bacteria isolated from healthy controls under nutrient-limited culture conditions. Conclusions The coexistence of multiple E. coli lineages in a host may help create and maintain a microbial environment that is beneficial to the host. As such, the low diversity of E. coli bacteria may be associated with unhealthy microenvironment in the intestine and hence facilitate the pathogenesis of diseases such as CRC.

The article presents the latest status of the Maidanak 1 m telescope, instruments and the related facilities of the Observatory as well as the science projects. The renovation of the 1 m telescope of Carl Zeiss (Germany) at the Maidanak observatory of the Ulug Bek Astronomical Institute (UBAI) AS of Uzbekistan has been made. All systems of the telescope were completely modernized based on modern standards, the main results of modernization are also described. All modernization works, as well as scientific research on this project are carried out in close cooperation of UBAI with the National Astronomical Observatories of the Academy of Sciences of the PRC in framework of the Agreement on cooperation between these organizations. The FOV has been enlarged and new CCD camera is mounted. The related facilities, like the observing circumstance monitoring system and the photovoltaic station, are also built for the observing support. The telescope and new camera will be tested and used for the science projects of the 1 m telescope. According to the collaboration agreement, a large-scale scientific project on a full survey of the northern sky in special photometric system - Stellar Abundance and Galactic Evolution (SAGE) survey will be carried out with the upgraded 1 m telescope. The main goal of the project is to measure the stellar atmospheric parameters for more than 500 million FGK stars. As other projects, the time domain science, like GRB, SNe searching, variable stars, also will be performed.

In this study, the utility and diagnostic accuracy of alkaline phosphatase on the surface membrane of neutrophils (mNAP) for bacteremia in patients with systemic inflammatory response syndrome (SIRS) was investigated and assessed. A total of 149 patients with SIRS were included. mNAP values were significantly higher in bacteremic SIRS group compared with that in non-bacteremic SIRS group (P < 0.001). The mNAP levels were significantly higher in SIRS patients with gram-negative bacteremia than those with gram-positive bacteremia. (P < 0.001). The receiver operating characteristic (ROC) curve analysis revealed the areas under ROC (AUC) of 0.806 for mNAP in differentiating SIRS patients with bacteremia from those without, similar to that for procalcitonin (PCT) (0.797). Combination of PCT and mNAP gave an AUC of 0.841. mNAP shares a similar diagnostic accuracy to PCT in predicting bacteremia in SIRS patients. The combination of mNAP and PCT provides a better prediction of bacteremia in patients with SIRS than either test alone.

Parkinson's disease is a neurodegenerative disorder characterized by mitochondrial dysfunction and oxidative stress. It is usually accompanied by an imbalance in mitochondrial dynamics and changes in mitochondrial morphology that are associated with impaired function. The objectives of this study were to identify the effects of rotenone, a drug known to mimic the pathophysiology of Parkinson's disease, on mitochondrial dynamics. Additionally, this study explored the protective effects of water-soluble Coenzyme Q10 (CoQ10) against rotenone-induced cytotoxicity in murine neuronal HT22 cells. Our results demonstrate that rotenone elevates protein expression of mitochondrial fission markers, Drp1 and Fis1, and causes an increase in mitochondrial fragmentation as evidenced through mitochondrial staining and morphological analysis. Water-soluble CoQ10 prevented mitochondrial dynamic imbalance by reducing Drp1 and Fis1 protein expression to pre-rotenone levels, as well as reducing rotenone treatment-associated mitochondrial fragmentation. Hence, water-soluble CoQ10 may have therapeutic potential in treating patients with Parkinson's disease.

Using first principle calculations method, we calculated the structural stability, electronic properties and hardness for three Re-doped hexagonal W 2 B 5 compounds. The electronic properties were carried out to discuss the effect of doped Re on the conductivity, chemical bonding components and orbital hybridization of W 2 B 5 . What is more, the hardness of these three doped crystals was calculated by a semiempirical method considering the role of metallic components. A Re-doped W 2 B 5 compound with a greater hardness value than that of pure W 2 B 5 was obtained. And the effect of doping on the hardness of hexagonal W 2 B 5 was discussed.

As an integral component of the surgical staging system, lymphadenectomy for patients with endometrial cancer (EC) remains controversial, particularly in clinical stage I disease that includes not only low-risk, but also high-risk subgroups. In order to maximize the therapeutic effect of lymph node excision for high-risk patients who can potentially obtain survival benefits from it while minimizing its reverse effects in low-risk patients, pre-operative risk stratification of lymph node metastasis is necessary. The upregulation of microRNA-205 (miR-205) in carcinoma of the endometrium has been consistently reported recently and has been found to correlate with poor survival. The current study aimed to investigate whether the overexpression of miR-205 in curettage samples of EC could identify patients who are at a high risk for lymph node metastasis prior to surgery and validate the role of miR-205 as a prognostic marker in EC. Relative quantification detection of miR-205 in curettage and hysterectomy specimens of patients with EC was performed. Prediction of lymph node metastasis based on miR-205 expression, as well as tumor type and grade in curettage samples, was performed for all EC patients and patients with clinical stage I disease. Moreover, survival analysis was conducted. It was observed that miR-205 was significantly and consistently elevated in the curettage and hysterectomy samples of EC relative to normal controls. Furthermore, the overexpression of miR-205 could predict lymph node metastasis with a high accuracy and was revealed again to be associated with a poor prognosis in EC. Prospective and multicentric studies are required to further clarify the value of miR-205 as a promising predictor to stratify risk for lymph node metastasis in EC.

Mitochondrial dysfunction and oxidative stress are the major events that lead to the formation of mitochondrial permeability transition pore (mPTP) during glutamate-induced cytotoxicity and cell death. Coenzyme Q10 (CoQ10) has widely been used for the treatment of mitochondrial disorders and neurodegenerative diseases. Comparing to traditional lipid-soluble CoQ10, water soluble CoQ10 (Ubisol-Q10) has high intracellular and intra-mitochondrial distribution. The aims of the present study are to determine the neuroprotective effects of Ubisol-Q10 on glutamate-induced cell death and to explore its functional mechanisms. HT22 neuronal cells were exposed to glutamate. Cell viability was measured and mitochondrial fragmentation was assessed by mitochondrial imaging. The mPTP opening was determined by mitochondrial membrane potential and calcium retention capacity. The results revealed that the anti-glutamate toxicity effects of Ubisol-Q10 was associated with its ability to block mitochondrial fragmentation, to maintain calcium retention capacity and mitochondrial membrane potential, and to prevent mPTP formation, AIF release, and DNA fragmentation. We concluded that Ubisol-Q10 protects cells from glutamate toxicity by preserving the integrity of mitochondrial structure and function. Therefore, adequate CoQ10 supplementation may be beneficial in preventing cerebral stroke and other disorders that involve mitochondrial dysfunction.

The morphology and development of the flowers of Anemoclema glaucifolium were studied with light and scanning electron microscopy, and compared with related genera. In Anemoclema all floral organs are initiated in a spiral sequence, while phyllotaxis is irregular spiral. The young sepals are crescent-shaped, but the young stamens and carpels are hemispherical. The developmental sequence of the microspores in the stamens is centripetal, following the initiation sequence of the stamens. The mature ovule is anatropous and unitegmic. Our results support the inclusion of Anemoclema within Anemoneae based on the floral developmental and morphological features: carpels bearing one median fertile ovule and two or three lateral sterile ovules. Anemoclema also possesses traits that unify it with Clematis, that are lacking in Anemone: (1) centripetal anther maturation (vs. centrifugal or bidirectional), and (2) conspicuous appendage at the ventral base of the ovule funicle (vs. inconspicuous appendage). These characters support a close relationship to Clematis, which complement results from molecular inferences.

Both wild-type and mutated beta-amyloid (Aβ) peptides can elicit an immune response when delivered subcutaneously. However, only mutated forms of Aβ can sensitize dendritic cells when administered intravenously or intraperitoneally. To understand the role of mutation and delivery routes in creating immune responses, and the function of dendritic cells as therapeutic agents, we used fluorescent-conjugated WT Aβ1-40 (WT40) and artificially mutated Aβ1-40 (22W40) peptides to treat dendritic and Langerhans cells from young and/or old mice at different time points. The cell types were analyzed by flow cytometry and confocal microscopy to identify differences in function and antigen presentation, and Luminex and Western blots for cell activation and associated mechanisms. Our results demonstrated that the artificial mutant, 22W40, enhanced dendritic cell's phagocytosis and antigen presentation better than the WT40. Interestingly, Langerhans cells were more effective at early presentation. The artificial mutant 22W40 increased CD8α+ dendritic cells, CD8+ T-cells, and IFN-γ production when co-cultured with self-lymphocytes and dendritic cells from aged mice (30-month-old). Here, the 22W40 mutant peptide has been found to be potent enough to activate DCs, and that dendritic cell-based therapy may be a more effective treatment for age-related diseases, such as Alzheimer's disease (AD).

Oxymatrine (OMT), an active constituent of Chinese herb Sophora flavescens Ait, has been proved to possess anti-tumor, anti-oxidant, anti-inflammatory, and anti-apoptotic activities. Previous study has demonstrated that OMT had protective roles on multiple in vitro and in vivo brain injury models including regulation of apoptosis-related proteins caspase-3, Bax and Bcl-2. In this study, we investigated whether this protective effect could apply to neonatal hypoxic-ischemic brain damage. Seven-day-old Sprague–Dawley rats were treated with the left carotid artery ligation followed by exposure to 8% oxygen (balanced with nitrogen) for 2.5 h at 37 °C. In sham group rats, neither ligation nor hypoxia was performed. After two successive days intraperitoneal injection with OMT (30, 60 and 120 mg/kg), Nimodipine (1 mg/kg), and saline, brain infarct volume was estimated, histomorphology changes were performed by hematoxylin–eosin (HE) staining as well as electron microscopy. In addition, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC), as well as production of malondialdehyde (MDA) were assayed in ipsilateral hemisphere homogenates to evaluate the redox status after hypoxic-ischemic. Expression of apoptosis-related proteins Caspase-3, Bax and Bcl-2 in brain were analyzed by western-blot analysis and immunofluorescence. Administration of OMT significantly decreased brain infarct volume and the percentage of injured cells, and ameliorated histopathology and morphological injury as well. Furthermore, OMT obviously increased the activities of SOD, GSH-Px, CAT and T-AOC, and decreased MDA content. Western-blot analysis showed a marked decrease in Caspase-3 expression and increase in the ratio of Bcl-2/Bax after OMT (120 mg/kg) post-treatment as compared with hypoxic-ischemic group. These results suggest that OMT exerts a neuroprotective effect against hypoxic-ischemic brain damage in neonatal rats, which is likely to be mediated through increasing anti-oxidant enzyme activities and inhibiting cell death.

To improve the heavy-duty vehicles’ gear shock solution during shifting and improve shifting comfortable, a research direction is improve the performance of lockpin synchronizer. Through the analysis of the main technical parameters of lockpin synchronizer, got the main research direction to improve the performance of lockpin synchronizer. The synchronizer structure optimization design was discussed. And the synchronizer is simulated and analyzed using the virtual prototype technology, which give a way to improve the performance of synchronizer.

In this paper ,the finite element model of the lei-ring was established in ANSYS software,the sealing performance of hydraulic support column piston was analyzed.Also,the numerical simulation analysis was made of the impact of column working pressure on the sealing performance,and a series of the integrated equivalent stress and contact pressure images of sealing ring when working were got. From those images,the location most prone to failure can be concluded.All of work can provide a theoretical reference for the design and use of drum sealing ring used on hydraulic support upright column.

In view of the high efficiency modernization coal demand, in this paper, the hydraulic support moving velocity influence factors were studied. Building simulation model of the thrust jack of hydraulic support with the simulation software AMESim, and run the simulation. Comparing the simulation results by setting different parameters value. It is concluded that the rated flow of pump station and hydraulic controlled check valve opening quantity will affect the speed of hydraulic support moving frame. This result provides reference for the optimal design of hydraulic support and improving the efficiency of coal mining. Key words: Moving velocity of hydraulic support; Rated flow; Hydraulic controlled check valve; AMESim 1 Tntroduction In the process of coal mining,the movement of hydraulic support needs in a timely manner with coal mining progresses, thrust jack plays a vital role for the movement of the hydraulic support. Therefore, it is very meaningful to research the influence factors of hydraulic support moving velocity With thrust control loop as the breakthrough point . 2 The working principle of the thrust control loop The movement of the hydraulic support and push the slide are achieved by thrust jack. Thrust jack is located in the middle part of the base of the hydraulic support, its end hinged with the base of the hydraulic support, the other end is connected with flexible scraper conveyor. When the hydraulic support moving, uninstall first, then the hydraulic controlled check valve make high pressure liquid into the piston rod cavity of thrust jack, the liquid in piston chamber flow back. At the same time, make thrust jack cylinder to move forward with the support of conveyor, thus, the whole hydraulic support is pulled to the coal wall, to complete the move. when pushing the slide, make high pressure liquid into the piston chamber , the liquid in piston rod cavity flow back, and, make the piston rod out with the support of hydraulic support. so,the conveyor is pushed to the coal wall,it is completed.

To observe the effects of Danshen aqueous extract (DSAE) on the cerebral tissue and nerve stem cells in cerebral ischemia reperfusion (CIR) rats. The model rats were prepared by occlusion of the middle cerebral artery for 2 h and then by reperfusion. They were randomly divided into five groups: a control group, an CIR group and three DSAE-treated groups. As compared with the sham control group, there was significant increase (P < 0.05, P < 0.01) in the serum high-sensitivity C-reactive protein (hs-CRP) and interleukin-8 (IL-8) levels, interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α) levels, and IL-10 mRNA, TNF-α mRNA expression levels, function score, Infarct size, TUNEL + cell counts, cerebral transforming growth factor beta 1 (TGF-β1) positive expression and cerebral neuron specific enolase (NSE) levels, and decrease in fas-associated protein with death domain (FADD) and death-associated protein (Daxx) positive expression levels in the CIR group. Compared with CIR group, DSAE treatment dose-dependently significantly decreased serum hs-CRP, IL-8, IL-10, TNF-α levels, and IL-10 mRNA, TNF-α mRNA expression levels, function score, Infarct size, TUNEL + cell counts, cerebral TGF-β1 positive expression and cerebral NSE levels, and increase FADD and Daxx positive expression levels in the CIR + DSAE groups. Taken together, these results suggest that DSAE has a neuroprotective role in the CIR rats, which may be related to improvement of immunity function, proteins and genes expression.

A complete analysis of flat and stable optical comb generation based on the re-circulating frequency shifter has been analyzed and demonstrated in this paper. We find out the influence to the flatness of optical comb owing to amplifier relative intensity noise and modulator relative factors imperfect, such as input RF signals amplitude and phase deviation and modulator defect owing to manufacture for the first time. Moreover, to verify the theoretical analysis, a 16 comb lines and spacing 12.5 GHz RFS generation system have also been carried out, and the results are in good agreement with the theoretical analysis results.

To explore the change trend of cell viability, apoptosis and reactive oxygen species (ROS) production of peripheral blood neutrophils in in vitro culture.Neutrophils were isolated by density gradient centrifugation and cultured in medium containing 10% fetal bovine serum for diffentrent times in a fall humidified atmosphere with 5% COThe cell viability of neutrophils could be maintained above 90% at 24 h in culture in vitro, and there was no significant difference between culture in vitro at 0 h and 24 h (P0.05), but after culture in vitro at 72 h, the cell viability of neutrophils obviously droped, the count of apoptotic cells increased, and after culture in vitro at 96 h the neutrophils almostly all died and the production of ROS at 12 h significantly decreased as compared with that at 0 h.The cell viability of neutrophils at 24 h cultures in vitro can be maintained relative stable with cell viability above 90% and unobvious change of count of apoptotic cells, but the neutrophil function test of ROS should be carried out immediately after cell separation.

The HIV-1 membrane proximal external region (MPER) that is targeted by several broadly neutralizing antibodies (BNAbs) has been considered a potential immunogen for vaccine development. However, to date the immunogenicity of these BNAb epitopes has not been made sufficiently adequate. In the present work, we used live attenuated Salmonella as a platform to present the HIV-1 MPER 10E8 epitope in the fimbriae. The insertion of the 10E8 epitope into the fimbriae had no significant influence on the expression and the absorption capacity of bacterial fimbriae, nor on the virulence and invasiveness of the attenuated Salmonella. After oral administration of the vaccine construct to mice followed by 10E8 epitope peptide boost, specific antibody responses in serum and mucosa as well as memory lymphocytes in spleen and plasma cells in bone marrow were induced. We also found that the live attenuated Salmonella vector directed the immunity toward Th1 bias, induced Th1 and Th2 cytokine responses and stimulated significant B cell differentiation into GC B, memory B and plasma cells. Therefore, we propose that the live attenuated Salmonella constitutively expressing HIV-1 BNAb epitopes on the fimbriae will be an effective approach to improving immune microenvironment and enhancing the immunogenicity of HIV-1 epitope vaccines.

In order to reveal the relationship between the adsorption performance of adsorbents and their compositions, structure, and surface properties, the core-shell structured Fe₃O₄/MnO2 and Fe-Mn/Mn₂2 magnetic particles were systematically characterized using multiple techniques and their Cu adsorption behaviors as well as mechanism were also investigated in details. It was found that both Fe₃O4 and Fe-Mn had spinel structure and no obvious crystalline phase change was observed after coating with MnO₂. The introduction of Mn might improve the affinity between the core and the shell, and therefore enhanced the amount and distribution uniformity of the MnO₂ coated. Consequently, Fe-Mn/MnO₂ exhibited a higher BET specific surface area and a lower isoelectric point. The results of sorption experiments showed that Fe-Mn had a higher maximal Cu adsorption capacity of 33.7 mg · g⁻¹ at pH 5.5, compared with 17.5 mg · g⁻¹ of Fe₃O4. After coating, the maximal adsorption capacity of Fe-Mn/MnO₂ was increased to 58.2 mg · g⁻¹, which was 2.6 times as high as that of Fe₃O₄/MnO₂ and outperformed the majority of magnetic adsorbents reported in literature. In addition, a specific adsorption of Cu occurred at the surface of Fe₃O₄/MnO₂ or Fe-Mn/MnO₂ through the formation of inner-sphere complexes. In conclusion, the adsorption performance of the magnetic particles was positively related to their compositions, structure, and surface properties.

In this study, blood samples from newly HIV-1 infected men who have sex with men (MSM) were collected, and HIV-1 genotypes were identified based on gag p17-p24 and nef gene regions. We found that participants aged from 20 to 40 years old were the major infection group in Harbin. CRF01_AE was the predominant genotype, contributing to 84.7% of HIV-1 infections, followed by subtype B (4.7%), CRF07_BC (3.5%), and subtype B' (Thai B, 1.2%). Moreover, five unique recombinant forms (5.9%) were also identified, including genotypes 01B, 01C, and 01/02. The recombinant CRF01_AE/CRF02_AG was first reported in China. These results suggested that current HIV-1 genotype epidemic among MSM in Harbin is more complicated and that intersubtype recombinants have emerged. Therefore, timely regional epidemiological surveillance of HIV-1 genotype and development of prevention measures for new HIV-1 infections among MSM are quite important.

Rotational rheometer was employed to determine rheological properties of sodium alginate solutions of 3, 5 and 10wt.% concentrations. The results showed that temperature had a strong effect on the morphology of sodium alginate in aqueous solutions. To observe the anisotropic phase formation, Polarized optical microscopy (POM) experiments were performed. It revealed the presence of briefringence in 3, 5 and 10wt.% sodium alginate solutions.

Typical challenges that manufacturing enterprises are facing now are compounded by lack of timely, accurate, and consistent information of manufacturing resources of shop floor. This paper presents a real-time Manufacturing Resources Tracking and Tracing Framework (MRTTF) based on Auto-ID devices such as RFID. Then, a configuration solution of equipping traditional manufacturing resources with Auto-ID devices is described. And the real-time information tracking flow of attached manufacturing resources (Men, Machines and Materials) is also illustrated. The presented framework and solution will provide real-time information of manufacturing resources for production mangers or supervisors to make accurate and optimal decisions.

The Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) General Survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects both in the pilot survey and the first year general survey are included in the LAMOST First Data Release (DR1). The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The general survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2,955,336 spectra, of which 1,790,879 spectra have observed signal-to-noise S/N >10. All data with S/N>2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2,204,696 spectra, of which 1,944,329 are stellar spectra, 12,082 are galaxy spectra and 5,017 are quasars. The DR1 includes not only spectra, but also three stellar catalogues with measured parameters: AFGK-type stars with high quality spectra (1,061,918 entries), A-type stars (100,073 entries), and M stars (121,522 entries). This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. Description of the FITS structure of spectral files and parameter catalogues is also provided., 39 pages, 13 figures

We present a quantitative estimate of the relativistic corrections to the thermal SZ power spectrum produced by the energetic electrons in massive clusters. The corrections are well within 10% for current experiments with working frequencies below v 350 GHz. Moreover, the corrections appear to be slightly smaller at higher l or smaller angular scales. We conclude that there is no need to include the relativistic corrections in the theoretical study of the SZ power spectrum especially at low frequencies unless the SZ power spectrum is used for precision cosmology.

In this paper, we employed first-principle calculations to investigate the elastic properties, electronic properties and hardness of diamond and hexagonal W2B5 compounds under high pressure. The elastic properties were carried out to discuss the structural stability and the bond components of diamond and hexagonal W2B5. The electronic properties were presented to analysis the change of the bond components for W2B5. In addition, the hardness of these two crystals under high pressure was calculated by a semi-empirical method considering the role of metallic components and the effect of pressure on the hardness of diamond and hexagonal W2B5 was discussed.

The authors observed the spectrum of third-order harmonic (TH) emission of the plasma channel in atmosphere by focused ultra-short laser pulses under various conditions. The authors used pulsed Ti: sapphire chirped pulse amplification (CPA) femtosecond laser system, with the central wavelength at 795 nm, repetition rate of 10 Hz, pulse duration of 30 fs and the pulse energy of 12 mJ, focused by a concave mirror with the focal length of 0.5 m, which can generate about 10(13) W x cm(-2) of power intensity. Under this condition, the dynamic balance between nonlinear Kerr self-focusing and plasma defocusing can support a long plasma channel in the interaction of the high intense laser pulses and gaseous media, and the interaction length between the laser pulse and air is greatly elongated, which is helpful to generating third-order harmonic emission. The full width at half maximum (FWHM) of the generated third-order harmonic spectrum is 15 nm with the central wavelength at 265 nm in the forward direction. The spectra of third-order harmonic emission red shift when the laser pulse is positive chirped. On the contrary, the spectra of third-order harmonic emission blue shift when the laser pulse is negative chirped. Proper dispersion can increase the intensity of third-order harmonic spectrum peak and sharped the spectrum peak. With the group velocity dispersion (GVD) of the pulses equal to +1.3 x 10(5) fs2, the peak of third-order harmonic spectrum red shifts and the group velocity dispersion of laser pulses equals to zero fs2. The experiment shows that the rising wing of pulses can obtain higher third-order harmonic conversion efficiency than the falling edge of the pulses. In addition, acoustic-optic programmable dispersive filter (AOPDF) in the laser system can control the spectrum shape of the laser. Changing the hole position of acoustic-optic programmable dispersive filter can also shift the spectrum shape of third-order harmonic emission in a certain range. Studies on spectral characteristics of the third-order harmonic emission in plasma channels at atmosphere are very useful to developing the technology of tuning the radiation in generation of ultraviolet or even soft X-ray domain.

In this paper, we bring forward a new approach for SAR imaging using fractional Fourier transform (FRFT). For synthetic aperture radar (SAR), the echo from the ground can be regarded approximately as a chirp signal, and the FRFT is a powerful way to concentrate the energy of a chirp signal. A two stepSAR imaging algorithms is suggested, and experimental results show that the efficiency and accuracy of the proposed method are much better than those of the Chirp Scaling algorithm (CSA). Also for the reason it take only two steps to form the image in the fractional Fourier domain, this method is much simple in implementation.